JPS63193965A - Coating material for heat-resistant precoat metal - Google Patents

Abstract

PURPOSE:To obtain the titled material capable of forming a coating film which is outstanding in dent resistance improved in gloss and bending processability when coated on a metal base plate, by incroporating a fluorocarbon polymer resin of specified melting point in a thermoplastic aromatic polythersulfone resin. CONSTITUTION:The objective coating material can be obtained by incorporating (A) 100pts. by wt. of a thermoplastic aromatic polyethersulfone resin [e.g., a resin constituted of recurring unit of formula (n is 2-1,000)] with (B) 20-800pts. by wt. of a fluorocarbon, polymer resin with the melting point regulated between 280 and 315 deg.C (pref. a copolymer from tetrafluoroethylene and perfluoroalkyl perfluorovinyl ether). The thickness of the resultant coating film is pref. 10-20mu on a dry basis.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a coating material for pre-coated metal with excellent heat resistance. In particular, when coated on a metal substrate, it has excellent indentation resistance, gloss, and bending properties. The present invention provides a coating material that forms a coating film with improved properties.

[Conventional technology]

Thermoplastic aromatic polyether sulfone resin (PE
(hereinafter referred to as PTFE) and 47-fluorinated ethylene resin (hereinafter referred to as PTFE)
When the composition is coated on a metal substrate, it provides a coating film with excellent heat resistance, Ta lubricity, and non-adhesion. This coated material is used as a material for cooking utensils such as frying pans and bread baking molds, taking advantage of its non-stick properties during cooking.

This composition is coated onto a material, heated and dried, and then subjected to molding processes such as bending to produce cooking utensils. That is, it is often used as a composition for coating materials for pre-coated metals.

Therefore, in addition to the above-mentioned heat resistance, lubricity, and non-viscous properties, the coating must not leave impressions when scratched, and can withstand bending, so that it can be used on the surface of the final product. Good gloss is also required.

A composition consisting of PES and PTFE is disclosed in, for example, Japanese Patent Application Laid-open No.
-83453, Japanese Patent Publication No. 53-34134, PES is dissolved in an inert solvent, PES is
A composition in which TFE is finely dispersed is applied to the base material, and
An example is given in which the coating is heated and dried at a temperature within the range of 0°C to 450°C.

[Problem that the invention seeks to solve]

Japanese Patent Application Publication No. 50-83453, Japanese Patent Publication No. 53-3413
When the composition of PES and PTFE disclosed in Publication No. 4 is coated on a material and dried by heating to the above-mentioned temperature range, the finished coating film is uneven and scratches easily with nails, etc. There were problems in that there were impressions and the gloss was low and the appearance was poor.

Therefore, it is desired to develop a heat-resistant coating material for pre-metals that has excellent heat resistance, bending workability, and indentation resistance, as well as good gloss and appearance.

The present invention aims to solve this problem.

[Means for solving problems]

As a result of various studies regarding this problem, the present inventors have found that the problem with the prior art is that, since PTFE does not have a solvent, it is suspended in a PES solution, but this PTl:E is made into uniform fine particles. It is difficult to disperse, and PTFE has the property of being difficult to get wet with other 19 materials.
This makes the coating lubricious and non-adhesive, but it is therefore difficult to completely wet the particle surface at the suspension stage. Furthermore, PTFE has a high melting point of 320 to 327°C (at 450°C) J1
1 heat, which is normally done during pre-coated metal manufacturing.
It was discovered that the short heating period of about 3 minutes was due to the fact that P T E did not completely melt.We conducted further research to improve these causes and completed the present invention. did.

In the present invention, 20 parts by weight or more and 800 parts by weight or less of a fluorocarbon polymer resin whose melting point is adjusted to a range of 280 to 315°C are blended with 100 parts by weight of a thermoplastic aromatic polyether "norphin-based resin." Made of heat resistant pre-coated metal Kawanami material.

The present inventors have discovered that conventional problems such as non-uniformity of the coating film, tendency to form impressions, and low gloss when using a composition consisting of PES and PTFE as a coating material are caused by the use of PTFE. We solved the problem and replaced PTFE with a melting point of 280-31.
P as fine particles of fluorocarbon polymer resin at 5℃
When used dispersed in an ES solution, the PES solution has excellent wetting properties, and the heating conditions are 380-450℃.
It melts even under the normal pre-coat metal production conditions of 1 to 3 minutes at 0℃, forming a uniform and glossy coating, and maintains heat resistance, lubricity, and non-adhesion properties equivalent to those using PTFE. He discovered something special.

In the present invention, the thermoplastic aromatic polyether sulfone resin (PES) includes, for example, a resin consisting of repeating units represented by the following general formula.

n is usually a positive integer of 2 to 1.000. Also, examples of the fluorocarbon polymer resin of the present invention having a melting point adjusted to 280 to 315°C include copolymers of tetrafluoroethylene and perfluoroalkyl perfluorovinyl ether; Copolymers of ethylene ester, perfluoroalkyl perfluorovinyl ether, and 67-propylene are preferred; the melting point of these copolymers can be adjusted by changing the ratio of copolymers. Increasing the beating melting point can be achieved by increasing the proportion of tetrafluoroethylene and hexafluoride propylene, and lowering the melting point can be achieved by increasing the proportion of perfluoroalkyl perfluorovinyl ether. Specifically, "Teflon PFAJ" manufactured by Mikata Fluorochemical Co., Ltd. is available as such a copolymer.

In the composition of the present invention, the weight ratio of PES to fluorocarbon polymer resin having a melting point of 280 to 315°C is PES'1
The amount is 20 to 800 parts by weight, particularly preferably 80 to 150 parts by weight, of the fluorocarbon polymer resin having a melting point of 280 to 315° C. per 1.00 tonne parts.

If the amount of fluorocarbon polymer resin with a melting point of 280 to 315°C is less than 20 parts by weight relative to the PE5100 heavy foot part, the pre-coated metal coating material will have poor creeping properties, and
When the amount is more than 1 part ff, the indentation resistance deteriorates, and the bending workability of the coated precoat metal and the adhesion to the object to be coated also deteriorate, making it unsuitable as a heat-resistant precoat metal coating material.

Fluorocarbon polymer resins with a melting point of less than 280°C will result in poor heat resistance for the coating material, while fluorocarbon polymer resins with a melting point of more than 315°C will result in uneven coatings, which may cause scratches with nails. There are defects such as indentation, low gloss, and poor appearance.

A method of forming a coating film on a roof material according to the present invention will be described.

PES is used after being dissolved in a solvent at a concentration of 1 to 50% by weight.

The solvent is not particularly limited, but amide solvents such as dimethylformamide and N-methylpyrrolidone are preferred from the viewpoint of solubility, and xylene,
A mixture of solvents such as cyclohexanone, methyl edyl ketone, and perchlorethylene can be used.

Fine powder of fluorocarbon polymer resin and other components as required are dispersed and mixed into this PES solution. For this dispersion mixing, a conventional three-roll mill, ball mill, dipper mixer, etc. can be used.

Other components that may be added include a color vehicle, a dispersant, a wetting agent, and a leveling agent.

Examples of color vehicles include pigments, but they must have good heat resistance, and aluminum powder, silicon compounds such as aluminum silicate, magnesium silicate, and silica powder, and graphite, such as strontium chromate and zinc chromate, are used as color vehicles. Examples include chromium-based antirust pigments such as -1-1 chromium oxide, and fired pigments made of composite oxide compounds obtained by heat treatment at 800 to 1.200°C.

As a dispersant, cellulose derivatives such as Eastman Co., Ltd.
Kodak product product name EAB-171-2, EAB-5
5-0,01, Vinyl chloride polymer resin such as U.S.A.
An example is VAG HlYMCH manufactured by C.C.

Examples of the leveling agent include acrylic polymer resins such as Remix RL-4 (trade name, manufactured by Mikata Kurashio Kagaku Co., Ltd.), and Modaflow (trade name (trade name), manufactured by Monsanto Chemical Co., Ltd. in the United States).

The PES solution of the fluorocarbon polymer resin obtained in this manner is coated onto the base metal. Coating methods include roll coater, flow coater,
It is common to apply by spraying or the like, but this is not intended to be limiting in any way.

The thickness of the dry coating is in the range of 7 to 40 microns, but a thickness of 10 to 20 microns is preferred from the viewpoint of heat resistance, indentation resistance, corrosion resistance, and bending processability.

After coating, the solvent is evaporated in a heating furnace and then a melting process is performed, preferably at a heating temperature of 380 to 450°C and a heating time of 1 to 3 minutes.

The object to be coated is generally a heat-resistant metal material such as an aluminum plate, an aluminum-plated steel plate, a stainless steel plate, or a steel plate, and may be subjected to chemical conversion treatment such as chromate treatment depending on the required performance.

The metal plate coated with the heat-resistant pre-coated coating material of the present invention and melt-treated has heat resistance up to about 260°C, and can be used for cooking utensils such as frying pans, bread baking molds, and gratin dishes.
Suitable as lining material for inner boxes of ovens, ranges, etc.

When manufacturing cooking utensils, painted plates can be molded, but it is also possible to paint already molded materials.

[For production]

In the present invention, whereas conventionally PTFE was suspended in a PES solution, a fluorocarbon polymer resin with a melting point adjusted to 280 to 315°C, such as a copolymer of tetrafluoroethylene and perfluoroalkyl perfluorovinyl ether, is used. The use of PES solution improves wetting of the fluorocarbon polymer resin fine particles with the PES solution, resulting in better dispersibility.Also, the melting point can be lowered to 280-315°C, compared to 320-327°C for PTFE, so it can be used after the coating dries. In the melting process, the fluorocarbon polymer can be melted and evenly distributed even when heated for a short time of 1 to 3 minutes at 380 to 450°C, resulting in a heat-resistant precoated metal coating with good indentation resistance, bending workability, and gloss. It is thought that this makes it possible.

〔Example〕

The present invention will be explained by examples, but the present invention is not limited thereto. Note that parts and % indicate parts by weight and monomer % unless otherwise specified.

Example 1 Thermoplastic polyethersulfone resin PES-200
(trade name: Goctrex, manufactured by 1.C.1, UK) was dissolved in 70 parts of N-methyl-2-pyrrolidone, and this was used to obtain a heat-resistant precoated metal coating material with the following formulation.

30% solids solution of PES-200
53 parts Teflon PFA (trade name manufactured by Mikata Fluorochemical Co., Ltd.) 16 parts Modaflow (trade name manufactured by Monsando Chemical Co., Ltd., USA) 0.4 parts -Methyl-2-pyrrolisine 30.6 parts 100.0 parts
The production of the part-covering material suspension liquid involves mixing the above components,
Dispersion was performed using a ball mill. This coating material suspension liquid was applied to a chromate-treated steel plate with a thickness of 0.5rLvn using a roll coater so that the dry coating film was 20μ, and the solvent was evaporated in a heating furnace at 200°C for 1 minute. ℃
Heat and melt for 2 minutes. Table 2 shows the performance evaluation results of the pre-coated metal coated with this coating material.

Examples 2 to 5 Comparative Examples 1 to 3 Coated steel plates were prepared using the same procedure as in Example 1 and using formulations not shown in Table 1. The results of these performance evaluations are shown in Table 2.

〔Effect of the invention〕

By coating the coating material of the present invention on the base metal,
While maintaining the same heat resistance, lubricity, and non-adhesive properties as when conventional PTFE is used as a component, it has the disadvantages of conventional coating materials such as uneven coating, easy impressions, and low gloss. By completely solving this problem, we were able to provide a coating material for pre-coated metal that has excellent appearance, gloss, indentation resistance, bending workability, and lubricity.

This is a great invention for practical use.

Claims (1)

[Claims] A heat-resistant precoated metal coating comprising 20 parts by weight or more and 800 parts by weight or less of a fluorocarbon polymer resin whose melting point is adjusted to a range of 280 to 315°C to 100 parts by weight of a thermoplastic aromatic polyether sulfone resin. Material.